Practice problems · Oral liquids · 5 worked
Oral liquid dosage calculation practice problems
An oral liquid problem asks how many milliliters of a solution or suspension carry the ordered dose. The label gives a concentration, such as 250 mg per 5 mL, and the order gives the dose. Watch the volume in that concentration: it is not always 1 mL.
The rounding rule on this page
Every answer here is rounded once, at the end, under one stated rule: nearest tenth, half rounds up, except tablets and capsules, rates in milliliters per hour and drip rates in drops per minute, which go to the nearest whole number, half rounds up. Your program's rule may differ, and on an exam it is the one that counts.
Work each problem on paper first, then open its solution. Each one is one of the 20 problems in DoseReady's Oral liquid family, with the numbers the app drew for it.
No licensed clinician has reviewed the problem set. Where a problem and its source disagree, trust the source and what your program teaches.
Problem 1 of 5
The order reads 500 mg of amoxicillin oral suspension by mouth every eight hours. The bottle is labeled 250 mg per 5 mL. How many milliliters are drawn into the oral syringe?
Show the worked solution
Dimensional analysis
500 × 5 ÷ 250 = 10
Ratio and proportion
250 mg is to 5 mL as 500 mg is to x
500 × 5 ÷ 250 = 10
x = 10 mL
Formula method
- D (desired)
- 500 mg
- H (have)
- 250 mg
- Q (quantity)
- 5 mL
D ÷ H × Q
500 × 5 ÷ 250 = 10
- The working comes to
- 10 mL
- The answer under the stated rule
- 10 mL
- Nearest tenth, half rounds up.
What each slip gives here
- Decimal point one place out100 mL or 1 mL
- Conversion factor inverted25,000 mL
- Conversion skipped500 mL
What this problem is built from
Problem 2 of 5
The order reads 80 mg of furosemide oral solution by mouth every morning. The bottle is labeled 10 mg per milliliter. How many milliliters are drawn into the oral syringe?
Show the worked solution
Dimensional analysis
80 × 1 ÷ 10 = 8
Ratio and proportion
10 mg is to 1 mL as 80 mg is to x
80 × 1 ÷ 10 = 8
x = 8 mL
Formula method
- D (desired)
- 80 mg
- H (have)
- 10 mg
- Q (quantity)
- 1 mL
D ÷ H × Q
80 × 1 ÷ 10 = 8
- The working comes to
- 8 mL
- The answer under the stated rule
- 8 mL
- Nearest tenth, half rounds up.
What each slip gives here
- Decimal point one place out80 mL or 0.8 mL
- Conversion factor inverted800 mL
What this problem is built from
Problem 3 of 5
The order reads 15 mg of morphine sulfate oral solution by mouth every four hours as needed. The bottle is labeled 10 mg per 5 mL. How many milliliters are drawn into the oral syringe?
Show the worked solution
Dimensional analysis
15 × 5 ÷ 10 = 7.5
Ratio and proportion
10 mg is to 5 mL as 15 mg is to x
15 × 5 ÷ 10 = 7.5
x = 7.5 mL
Formula method
- D (desired)
- 15 mg
- H (have)
- 10 mg
- Q (quantity)
- 5 mL
D ÷ H × Q
15 × 5 ÷ 10 = 7.5
- The working comes to
- 7.5 mL
- The answer under the stated rule
- 7.5 mL
- Nearest tenth, half rounds up.
What each slip gives here
- Decimal point one place out75 mL or 0.8 mL
- Conversion factor inverted30 mL
- Conversion skipped15 mL
- Rounded to the wrong precision8 mL
“Rounded to the wrong precision” is the same working rounded to some other step, such as a half, a quarter or a hundredth, or left unrounded.
What this problem is built from
Problem 4 of 5
The order reads 20 g of lactulose solution by mouth daily. The bottle is labeled 10 g per 15 mL. How many milliliters are poured into the medicine cup?
Show the worked solution
Dimensional analysis
20 × 15 ÷ 10 = 30
Ratio and proportion
10 g is to 15 mL as 20 g is to x
20 × 15 ÷ 10 = 30
x = 30 mL
Formula method
- D (desired)
- 20 g
- H (have)
- 10 g
- Q (quantity)
- 15 mL
D ÷ H × Q
20 × 15 ÷ 10 = 30
- The working comes to
- 30 mL
- The answer under the stated rule
- 30 mL
- Nearest tenth, half rounds up.
What each slip gives here
- Decimal point one place out300 mL or 3 mL
- Conversion factor inverted13.3 mL
- Conversion skipped20 mL
What this problem is built from
Problem 5 of 5
A child is to receive 400 mg of azithromycin by mouth once daily. The reconstituted suspension is labeled 200 mg per 5 mL. How many milliliters are drawn into the oral syringe?
Show the worked solution
Dimensional analysis
400 × 5 ÷ 200 = 10
Ratio and proportion
200 mg is to 5 mL as 400 mg is to x
400 × 5 ÷ 200 = 10
x = 10 mL
Formula method
- D (desired)
- 400 mg
- H (have)
- 200 mg
- Q (quantity)
- 5 mL
D ÷ H × Q
400 × 5 ÷ 200 = 10
- The working comes to
- 10 mL
- The answer under the stated rule
- 10 mL
- Nearest tenth, half rounds up.
What each slip gives here
- Decimal point one place out100 mL or 1 mL
- Conversion factor inverted16,000 mL
- Conversion skipped400 mL
What this problem is built from
Practice under your own program's rules
In DoseReady you enter your program's passing score, notation and rounding rule once. Every answer is graded under that rounding rule, and each worked solution is written in your notation where the problem allows it.
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Exam practice, never for patient care.
Guides
Other problem families
- Unit conversion practice problems for nursing students
- Tablet and capsule dosage calculation practice problems
- Injectable dosage calculation practice problems
- Reconstitution dosage calculation practice problems
- mL per hr IV rate practice problems
- IV drip rate practice problems (gtt/min)
- Infusion time practice problems
- Weight-based dosing practice problems (mg/kg)